The present invention relates to a PCM signal recording technique, and more particularly to method and apparatus for recording a PCM signal suitable for a rotary-head type PCM recorder.
In the PCM recorder, as disclosed in Japanese unexamined patent publication No. 58-173934 laid open on Oct. 12, 1983 (Japanese patent application No. 57-55660 filed on Apr. 3, 1982), a PCM signal (1 word) having a sampling frequency of 48 KHz or 44.1 KHz and the number of quantization bits of 16 is recorded by eight bits. (The eight bits are called one symbol). In the rotary head type PCM recorder for recording the PCM signal on a magnetic tape by the rotary head, the data sequence is recorded so that original PCM signals may be reconstructed in each track as disclosed in Japanese unexamined patent publication No. 58-188314 laid open on Nov. 2, 1983 (Japanese patent application No. 57-69915 filed on Apr. 26, 1982).
On the other hand, long time recording in which a recording time of the PCM signal to the recording medium is approximately two times as long as that of conventional recording may be attained by setting a sampling frequency of the signal to be recorded such as an audio signal to 32 KHz and non-linearly quantizing the signal by 12 bits. However, since one word consists of 12 bits, the conventional method of recording the signal by symbol cannot be used.
A technical trend of rotary-head type digital audio tape recorder (R-DAT) is described in "DAT Meeting Activity" on pages 36-42, particularly pages 40-42 of ELECTRONICS, vol. 24, No. 10, 1984 published by EIAJ (Electronics Industries Association of Japan).